In mid-July we will be seeing a "460" or "GF104" GPU from NVIDIA. It should MSRP around $230 and have very good overclocking potential. The 450 and 455, "GF106" series GPU will hitting the ground in mid-August and will be retailing at $129 - $179 price points, these GPUs will be replacing the 250 series. The 240 will be replaced in August or September by a "GF108."
The most interesting product will of course be the GeForce GTX 460. The specifications as rumored thuis far show that the GPU will make use of all the components available on the GF104, which include 240 CUDA cores, and will feature 768 MB of GDDR5 memory across a 192-bit wide memory interface. That's pretty much everything available.